Mechanism for raising and lowering frame and mattress portions of hospital beds



June 1961 A. J. DONALDSO'N MECHANISM FOR RAISING AND LOWERING FRAME AND 2 Sheets-Sheet 1 MATTRESS PORTIONS OF HOSPITAL BEDS Filed NOV. 12. 1957 8| 5. i fl K U H 21 A A [3 l3 jg 74 Q, a a a a 0 53/ fik i 24// TQ E i: 8 na 92 I06 lo ARMAND J. DONALDSON INVENTOR.

HIS AGENT A. J. DONALDSON 2,9 8,758 MECHANISM FOR RAISING AND LOWERING FRAME AND MATTRESS PORTIONS OF HOSPITAL BEDS 2 Sheets-Sheet 2 Hi5 AGENT 2 6 S, S i H 6 3 8 3 i n/ b O. a 5 M fii J TM W m 1 36 Q 0 W W we 8 T A m 5 w w a 2 I Q\\\\ \4- 6 0 6 6 8 0 5 7 'I .1 ll

June 20, 1961 Filed Nov. 12. 195'? United States Patent Filed Nov. 12, 1957, Ser. No. 695,881 1 Claim. (Cl. -68) This invention relates to improvements in raising mechanisms for hospital beds and more particularly to mechanisms that may be selectively controlled by the patient to raise or lower various portions of the frame and mattress to the desired height, which raising or lowering of portions of a bed, usually requires manual manipulation, by an attendant or nurse, of cranks attached to the mechanism to perform this action.

The present device is so constructed that a patient may raise or lower either the head portionof the knee portion of the bed, selectively, by manipulation of switches, and to stop the movement of the portion being raised at any point between the maximum height to which it may be raised and the lowest position, and wherein safety limit switches will prevent movement of the respective portions of the bed and mattress beyond these limits, thereby protecting the motor and the gearing against overload and failure.

Various mechanisms have been proposed heretofore for controlling various movements of a hospital bed, but these for the most part, required either major adaptations or complete reconstruction of the type of hospital beds commonly in use, or they had to be built integral with the bed, which meantthat they could not be used on beds already in use.

The present device is so constructed that it may be readily adapted to hospital beds of any design or type, which utilizes a rotating shaft to raise or lower the respective portions of the frame and sectional mattress. The present device may be readily attached to each of the respective rotating shafts, by means of a chain, in such manner that the center distance of the chain and the bearings for the shaft are in a predetermined spaced relation, so that the chain may be readily kept tight, and thatthe power unit may be readily supported to any portion of the bed that is available, and attached thereto, as by clamps or bolts.

An object of the present invention isto provide a mechanism for selectively raising or lowering a selected portion of a hospital bed, by means of patient controlled switches.

Another object of the invention is to provide a mechanism for raising or lowering portions of a hospital bed and the sectional mattress thereon, which mechanism may be readily attached 'to a-conventional hospital bed, without material reconstruction of the bed on which it is to be attached.

Still another object of the invention is to' provide a device wherein the center distances between the sprockets remains in a predetermined set relation, thereby obviating the necessity of precision measurements for attaching the unit in a particular relation with respect to the shaft to be rotated.

Yet another object of the invention is to provide a bearing retainer unit, wherein the bearings are maintained in adjusted relation, and wherein the chain between the sprockets of the power unit and the shaft to be rotated, may be adjusted to the correct tightness.

With these objects in mind and others which will become manifest as the description proceeds, reference is to be had to the accompanying drawings in which like referthereof, in which:

FIG. 1 is a side elevational view of typical hospital bed, showing the units, for raising and lowering units installed thereon;

FIG. 2 is a sectional view taken on the line 22 of FIG. 1, looking in the direction indicated by the arrows;

FIG. 3 is a diagrammatic view of the wiring system, showing the motors, control switches, and portions of the longitudinally movable bed mechanism associated therewith;

FIG. 4 is a perspectvie view of the power and gear unit, showing a portion of a rotatable shaft connected thereto;

FIG. 5 is a side elevational view of the unit shown. in FIG. 4, but showing parts broken away and in section-to bring out the details of construction;

FIG. 6 is an elevational view of one form of the shaft spacer member, with parts broken away and with parts shown in section, to show the details of construction, and showing a shaft member mounted on ball bearings therein;

FIG. 7 is a modified form of shaft spacer member which utilizes a screw adjustment member within the length thereof so as to adjust the center distance between the sprockets of the power gear unit and the shaft, for raising or lowering the section of the bed frame which supports a sectional mattress thereon; and

FIG. 8 is a fragmentary, sectional view of the motor mount.

With more detailed reference to the drawing, the nu meral 1 designates generally a hospital bed having a mattress thereon, which mattress embodies sections 2, 4 and 6. The mattress sections are mounted on a structural framework, comprising members 8, 10 and 12, which members are mounted on a support frame 13 of the bed 1, with the member 8 being hinged on pivot 14 so the mattress portion 2 may be elevated by the movement of arm 16 upward or downward by the longitudinal movement of a rod or tubular member 18 which is pivotally attached thereto. A rotatable shaft 20 is provided with a sprocket 22 thereon, which shaft has a threaded connection with rod or tubular member 18, and which shaft 20 is fixed against longitudinal movement. Therefore, upon rotation of shaft 20, the threaded interconnection with the rod or tubular member 18 will cause longitudinal movement of member 18 in one direction or the other, depending upon the direction in which the sprocket 22 is rotated, and while the rod 18 is shown to be connected with an arm 16 for raising or lowering the frame member 8 and mattress section 2, by the manipulation of switch buttons 24 and 26, switch buttons 28 and 30 are provided to raise or lower the knee section of the bed, on opposite sides, as will be more fully described hereinafter.

Motor units, designated generally by the numerals 32 and 32a are suspended on any conventional, non-movable brace or truss members beneath the bed, and which units are identical in construction, except they are arranged in reverse order, to enable the interconnecting of the respective shafts with the respective power units, as the respective motor-gear units 32 will be maintained in the correct spaced relation without any measurement being necessary for installation.

The present motor-gear units, as shown in FIGS. 5 and 7, are of a character which are insulated from the bed on which they are supported, both from an electrical insulation standpoint and from a vibration standpoint, so as to give ultimate safety, and at the same time, give a minimum of noise and vibration to the bed, on which the patient is resting. The motor 34 is of a character which has insulating rubber mountings 36 at each end, which mountings are intermediate the motor 34 and a support brace 38. Furthermore, an electrical insulation universal coupling member 40 is interposed between the motor shaft 42 and the gear reduction shaft 44. This insulating coupling may be made of hard rubber, vulcanite, or other suitable material. The motor 34 is spaced upward from brace 38, so that no transfer of current is possible from the motor to any part of the frame on which the motor is mounted. A mounting base 46 is provided on which the support brace 38 is secured, as is the worm gear unit 48. The worm gear unit is welded or otherwise secured to the base 46, so that the motor and gear unit may be readily aligned. A pair of sub-base members 50 extend beneath base members 46 and have a rubber sleeve 52 positioned therebetween. The sub-base members 50 and the base member 46 have apertures formed therein, which apertures are aligned and through which a bolt 54 is passed. A further insulating grommet 56 is inserted in the aperture of sub-base 50, so as to maintain the base assembly in spaced apart, insulated relation with respect to sub-base members 50.

Pairs of upright members 58 rise from the sub-base members 50 and are connected together by cross bars 60, which are secured thereto by bolts 61, which enables the ready removal of the cross bars for the insertion thereof over transverse braces 61a. Holes 60a are provided in cross bars 60 for passing bolts therethrough and through the respective transverse braces 61a. The cross bars 60 each have an elastomer cushioning element 62 therebelow, to serve as a cushion between the cross bar 60 and the respective transverse braces 61a, so as to provide insulation between the motor unit and the frame of the bed to prevent transfer of vibration to the bed.

The worm gear unit 48 has an outwardly extending driven shaft 64, the shaft of which gear passes through a bearing 66 within bearing housing 68. A spacer sleeve 69 is telescoped over shaft 64, intermediate the worm gear unit 48 and the bearing housing 68. An arm 70 is secured to bearing housing 68 and extends laterally of shaft 64, and a similar bearing housing 72 is positioned on the opposite end thereof and carries a bearing 65 therein, which is similar to the bearing 66, which bearing 66 journals shaft 20, as mentioned above. A chain 74 surrounds sprocket 22 on shaft 20 and sprocket 76 on shaft 64, so that shafts 20 and 64 are maintained in a predetermined spaced relation, to maintain the chain 74 tight at all times.

A modified form of the bearing spacer element is shown in FIG. 7, wherein members 71 are tubular and are internally threaded with right and left hand threads to complementarily receive screw threaded member 73, so upon turning of a hexagonal portion 75 thereof, the center distance of the respective bearings may be varied. Lock nuts 77 are provided to hold the bearing housings spaced apart, and in fixed relation, when the bearings are adjusted to the desired center distances.

The motor units, for purposes of identification, when installed on a bed, have been identified as units 32 and 32a, which are supported beneath'the bed frame on transverse members 61a and bolts 63 pass through holes 60a in cross bars 60 and through complementary holes in transverse brace members 61a to maintain the units against undue movement. However, the arm 70 will automatically determine the exact center distance between shafts 20 and 64, or between shaft 64 on motor unit 32a and shaft 80, which shaft is mounted on the opposite side of the bed 1 from the shaft 20, and is parallel therewith. The sprockets 22 and sprockets 81 are attached to the respective shafts 20 and 80 by means of set screws 21, so as to maintain the sprockets against longitudinal or rotary movement with respect to the respective shafts.

While unit 32 has been described in some particularity with respect to being connected to shaft 20, the unit 32a is similar in all respects to unit 32, except the power gear unit is connected in driving relation with shaft 80, which shaft operates in substantially the same manner as shaft 20. The shaft 80 threadably connects with a longitudinally movable bar or tubular member 82, which member 82 has a lever connected thereto in substantially the same manner as longitudinally movable member 18, so upon rotation of shaft 80, which is screw threaded, the bar 82 will be moved longitudinally to actuate a lever (not shown) in substantially the same manner as the movable bar 18, on the opposite side of the bed, operates lever 16, except the lever, which is operated by movable bar 82, raises and lowers the knee portion of the bed frame and the corresponding mattress section.

The longitudinally movable bar or tubular member 82 has a projection 84 thereon, which projection is interposed between a pair of normally closed, spring actuated limit switches 88 and 90, which switches have outstanding arms to engage projection 84, when the projection is moved to the end limit of the travel thereof in the respective directions, as determined by the respective limit switches 88 and 90. However, upon opening the respective limit switches, the motor 32a will be stopped, as the circuit for rotating the motor in that direction will be open and will remain open until the other circuit is closed to move the longitudinal bar 82 in the opposite direction. The limit switches 88 and 90 are connected in series with switches 28 and 30, respectively, which switches 28 and 30 and limit switches 88 and 90 are connected within the respective circuits, which circuits 96 and 98 are connected to a source of electrical power by a conductor cord 92, so as to selectively energize motor 32a upon closing one of the switches 28 or 30. However, a conventional multi-point motor reversing relay 94 is connected within the circuits 96 and 98 to operate the motor 32a in either direction, upon one of the switches 28 or 30, as desired, as an interlock is provided between the switches, so only one switch can be closed at a time. It is to be pointed out that with both of the switches 88 and 90 closed, the motor 32a may be operated in either direction by selectively pressing the switch 28 or 30 and holding the respective switch in contact relation until it is desired to stop the motor. However, if the limit switch 88 or 90, which is connected in series with the switch 28 or 30, is open, the holding coil of the magnetic reversing relay 94 will permit only the closing of the circuit to the motor in which the closed limit switch is located. It is to be pointed out that any type conventional relay switch, which will give a reversing action, may be used so long as the switch performs the functions as set out above.

Limit switches 100 and 102 are provided on each side of projection 86 on movable bar 18, so upon longitudinal movement of the bar or tubular member 18, one of the other of the limit switches 100 or 102 will be opened, when the maximum limit of travel of projection 86 is reached, one of the switches 100 or 102, which are in series connection with movably operated switches 24 and 26, will be opened. The switches 24 and 26 are of the type that are opened upon release of pressure, so as long as both of the limit switches 100 and 102 are closed, either of the switches 24 or 26 may be pressed to run the motor 32 in the desired direction, to raise or lower the head portion of the bed, however, a safety interlock is provided, so that only one of the switches 24 or 26 may be closed at one time, so that only one circuit 104 or 106 can be energized at a time.

The switch 24 is in series in a circuit leading from limit switch 100 through circuit 104 to relay 108 to motor 32, and switch 26 is in series in a circuit leading from limit switch 102 through circuit 106 to relay 108 connected to motor 32. It will be seen that a small compact switch member, with only four small push button switches on a conductor cord 92 to a point within reach of the patient on the bed, which will enable the patient to selectively adjust the portion of the mattress to the height best suited to the wishes and comfort of the patient.

The conductor cord 92 may be of the conventional plug-in type, therefore, it may be used anywhere an electrical outlet is available,thereby minimizing the time and" work required of a nurse-or attendantto raise or lower a portion of the bed at the patients requirement.

Safety switches 110 and 112 are provided intermediate the power connections and motors 32a and 32, so that either or both of the motors may be rendered non-operable by the turning oflf of these switches, and since these switches are located out of the normal reach of a bed patient, the system is rendered immobile until the switches are turned on. These switches may be of the lock type, if desired.

The present device is so designed that it may be readily attached to practically any hospital bed that is equipped with cranks to rotate shafts, by removing the cranks and positioning the sprockets 22 or 81 at the desired location and tightening set screw 21 supporting the motor-gear units 32 and 32a on braces and installing limit switches, as set out above. However, in event of power failure, the cranks may be attached to shafts 20 or 80, and the portions of the bed may be raised or lowered thereby, in the manner originally designed.

Having thus clearly shown and described the invention, what is claimed as new and desired to secure by Letters Patent is:

A device for raising and lowering hingeably connected sections of a hospital bed, which bed has a supporting frame mounting said hingeable members for movement relative thereto, transverse support members mounted on and secured between members of said supporting frame, a screw threaded shaft extending along a side of said supporting frame, a longitudinally movable member threadably engaging said shaft upon turning movement of said shaft; which device for raising and lowering said hingeable members of said bed comprises, a sprocket attachably connected to said screw threaded shaft, an elongated base, a reversible motor and gear unit mounted on said base, a pair of sub-base members extending below said elongated base, resilient members positioned between said elongated base and said sub-base members, bolts passing through said sub base members and said elongated base and said resilient members to hold said elongated base and said sub-base members against relative lateral movement, upright members connected to said sub-base members near each end thereof and extending upward to cradle said motor and gear unit therein, a pair of upper cross bars adapted to pass above certain of said transverse support members on said supporting frame of said bed, means attachably securing each of said upper cross bars to a pair of said upright members so said cross bars will be substantially parallel with said sub-base members which extend below said elongated base, and which upper cross bars bridge certain of said transverse support members on said supporting frame, further resilient means interposed between said upper cross bars and said transverse support members on said supporting frame, means fixedly securing said upper cross bars and said transverse support members of said supporting frame together, said gear unit having a power output shaft, an elongated arm having apertures formed in each end thereof surrounding said screw threaded shaft and said shaft of said gear unit, a bearing complementally fitted on each of said respective shafts and positioned in each of said apertures in said arm, a sprocket fitted on and secured to said output shaft of said gear unit, an endless drive chain fitted on and surrounding said sprocket on said screw threaded shaft and said sprocket on said gear unit in driving relation, at least two electric circuits connected with said motor, a momentary, limit switch in each of said circuits, a projection mounted on said longitudinally movable member and positioned to move into contact relation with one of said switches upon longitudinal movement of said longitudinally movable member in one direction and to move into contact relation with the other of said limit switches upon movement in the opposite direction, and a power supply operatively connected to said circuits and to said motor.

References Cited in the file of this patent UNITED STATES PATENTS 660,750 Cunningham Oct. 30, 1900 2,185,215 McCobe et al. Jan. 2, 1940 2,458,720 Mertz Jan. 11, 1949 2,579,472 Chamberlin et al. Dec. 25, 1951 2,590,337 McNabb et al. Mar. 25, 1952 2,630,720 Gambrill Mar. 10, 1953 2,709,515 Abell et al. May 31, 1955 2,747,421 Thiel May 29, 1956 2,807,174 Helsel Sept. 24, 1957 FOREIGN PATENTS 417,147 Italy Jan. 8, 1947 

